X-ray apparatus



July 21, 1936. A. VERHOEFF X-RAY APPARATUS Filed Jan. 23, 1934 III-5% Patented July 21, 1936 PATENT OFFICE X-RAY APPARATUS Adrianus Verhoeff, Eindhoven, Netherlands, as-

signor, by mesne assignments, to N. V. Philips Gloeilampenfabrieken,

Eindhoven, Netherlands, a Dutch company Application January 23, 1934, Serial No. 707,975 In Germany January 24, 1933 6 Claims.

As is well-known, an X-ray tube may be combined with a high-voltage transformer to form a unit. In such units an intervening space has been left between the tube and the metal parts of the transformer and sometimes this space has been filled with oil, in which case the intervening space may be made smaller than if it contained air.

X-ray tubes having a wall portion protected against irregular electric charges, i. e. tubes having an equipotential wall portion or a double wall completely avoid the necessity of such an intervening space. This fact may be readily understood 'by keeping in mind that the electrostatic charges built up. on the inner surface of charged wall is placed a short distance therefrom.

In the case of a tube having an equipotential wall portion these electrostatic charges are evenly distributed over this wall portion and thus no appreciable potential differences can occur in this portion and the wall portion can be in contact with a body of definite potential. In a tube having a double wall portion, the electric charges areprevented from reaching the outer wall so that the potential of the outer wall is not affected to any extent by the electric particles starting from the discharge path. Thus, in the claims, the expression, X-ray tube having a wall portion protected against irregular charges is to include both an X-ray tube having an equipotential wall portion and an X-ray tube having a double wall.

The present invention relates to an X-ray apparatus in which part of the wall of the tube bears against the magnetic core of the transformer'either directly or through the intermediary of a comparatively thin insulating layer or metal member. According to the invention, the longitudinal axis of the tube is arranged perpendicular to the plane of the sheet-metal laminations forming the transformer core. As the core is usually narrower in this direction than in a direction parallel to the laminations, the size of the transformer core and the length of an equipotential portion of the wall of the X-ray tube may be brought into better mutual concordance than with a tube arranged parallel to the plane of the laminations. According to whether use is made of an X-ray tube insulated on both ends or on one end, the insulating tube portions protrude from both sides or from one side of the transformer core.

A symmetrical construction of an X-ray apparatus according to the invention may be obtained by dividing. the transformer into two parts and by arranging the X-ray tube between these two parts. In this case, it is of advantage to construct the parts of the transformer as shelltype transformers in which the legs of the cores are located on opposite sides of the Xray tube and in the same direction. The entire unit may be easily enclosed by a metal envelope. shape of the transformer core is preferably made to conform in this case to the circular crosssection of the tube which brings about a saving of space and ensures the correct position of the tube.

The invention will be more clearly understood by referring to the accompanying drawing in which, by way of example, one form of construction of an X-ray apparatus according to the invention is diagrammatically represented.

Figure 1 is a section taken perpendicular to the axis of the tube and shows one of the transformer halves in section, the other in elevation.

Figure 2 is a plan view, partly in section, taken parallel to the axis of the tube.

Figure 3 is a view showing the external appearance of the apparatus and one type of support for same.

An X-ray tube I is enclosed between two shelltype transformers 2 and 3 having magnet cores formed as sectors of a circle. On one side of the tube a sector-shaped opening 4 is formed for the passage of theX-rays and on the other'side an opening 5 of the same shape is formed which may serve for the attachment of supporting members. Trapezium-shaped high tension coils 6 and 1 located in the windows of the transformers, each supply half the operating voltage of the X-ray tube. One of these coils has a winding for the heating voltage of the incandescent cathode. The primary windings are located directly around the central legs 8 and 9, the primary winding visible in Figure 1 being denoted by I 0. For the purpose of insulation, there is left in the transformer windows outside of the windings, a space which is filled with insulating material II. The two transformers and the X-ray tube are surrounded by a common metal housing 12 provided with a centering tube [3 arranged in front of a window Id of the X-ray tube. One of the ends of the high-tension coils B and 1 is connected to the iron core of the transformer, this connection not being shown in the figure. The outer ends of the coils are connected by means of insulating conductors l 5 and I6 (see Fig. 2) to the terminals of the tube.

The 10 The tube I has a central portion I! of metal preferably of ferro-chrome, which bears directly against the transformer core. However, X-ray tubes of other types in which it is possible to keep the middle portion of the tube surface at the same potential may also be used. 'By an equipotential Wall portion should therefore not only be meant a metal portion of the wall itself. The

apparatus may be supported from a stand in different manners, for example, as shown in Fig; 3 by a bracket l8 secured to the transformer. A handle l9 facilitates the rotation about the axis 20 passing through the focal spot of the tube.

The apparatus represented is particularly suitable for dental purposes to' which, however, the possibility of application is not restricted.

X-ray apparatus according to the invention may also be employed for testing materials, e. g. crystalline bodies. In an apparatus as shown in the figures the tube may be provided for this purpose with two diametrically opposite windows so that a beam of rays may emerge from the apparatus through both the chamber 4 and the chamber 5' with the'result that two objects can be tested simultaneously. The chambers are excellently suitable in this case for housing therei cameras for taking the photographs. 7

What I claimis:

1. An X-ray apparatus comprising an X-ray tube having an equipotentialwallportion, a hightension supply transformer for said tube and assembled withthe tube to form a unit therewith, and supply leads for said tube connected to the output ends of said transformer, said transformer having a magnetic core consisting of parallel laminations, said X-ray tube being arranged with its longitudinal axis perpendicular to the plane of said laminations and bearing with said wall portion against said core without interposed hightension insulation. y

2. An -X-ray apparatus comprising an X-ray tube having a cylindrical envelope comprising an annular metal portion and vitreous portions sealed to the edges of said metal portion, a high-tension transformer for said tube assembled with the tube to form a unit therewith, and supply conductors for said tube connected to the output ends of said transformer, said transformer having a magnetic core comprising parallel laminations, said annular metal portion being arranged with its axis perpendicular to the plane of the laminations and bearing against said core without interposed high-tension insulation.

3. In combination, an X-ray tube and a hightension supply transformer therefor, said transformer comprising two series-connected transformer units having magnetic cores comprised of parallel laminations, and high-voltage supply leads for said tube connected to the output ends of said transformer units, said transformer units being symmetrically arranged on opposite'sides of the longitudinal axis of the 'X-ray tube and with the plane of the laminations perpendicular to said axis, said laminations bearing against the 'wall of said tube without interposed high-tension insulation, and a common housing surrounding said tube and transformer.

4. In combination, an X-ray tube and a hightension supply transformer therefor, said transformer comprising two series-connected shelltype transformer units having magnetic cores,

said cores having central legs and consisting of sector-shaped laminations arranged parallel to a plane which is perpendicular to the longitudinalaxis of said X-ray tube, and high-voltage supply leads for said tube connected to the free output ends of said transformer units, said trans former units being arranged on oppositesides of said axis and with the central legs of the mag netic cores in alignment, and a common housing surrounding said tube and transformer.

5. In combination, an X-ray tube and a hightension supply transformer therefor, said transformer comprising two series-connectedshelltype partial transformers having magnetic cores,

said cores comprising sector-shaped laminations arranged parallel. to a plane perpendicular to the longitudinal axis of saidX-ray tube, said partial transformers being symmetrically arranged on opposite sides of the longitudinal axis of the tube and said laminations being recessedat the top of the sector to form a cavity in which said X-ray, tube is fittingly mounted, and electric leads for said tube connected to the free output ends arranged with its longitudinal axis perpendicu- 50 lar to the plane ofsaid laminations and bearing at said wall portion against said core without interposed high-tension insulation.

'ADRIANUS VERHOEFF. 

